In a turbojet disk, such as a high pressure turbine disk, curved holes are provided that extend between one of the faces of the disk and the bottoms of tangential cells for retaining blades. These holes serve to inject cooling air. A similar arrangement is provided on certain high pressure compressor disks for bleeding air.
In addition, these holes are generally of section that is not circular; they are usually elliptical in section. Conventionally, these holes are inspected by means of eddy currents, requiring a plurality of appropriate probes to be inserted therein and requiring broaching to be performed on each occasion in order to scan the inside surface of the hole along parallel longitudinal strips. The purpose of performing eddy current inspection is to identify any anomalies in the surface state of the hole, and in particular the formation of small cracks in the surface or underlying it. Contact between the probe and the surface of the hole needs to be maintained throughout the broaching operation in order to ensure that the inspection is reliable. Unfortunately, such holes may be of varying section, i.e. of section that is not exactly the same over their entire length, and they may also present local variations in curvature.
A known system comprises a set made up of a plurality of curved arms, each carrying a probe containing an eddy current sensor. Each probe has a split end that is resiliently flexible and that contains the sensor. That system lacks sensitivity and accuracy since the surface area that is scanned during broaching is too large, and above all because it is not certain that good contact will be obtained between the outside surface of the probe, on the best point thereof, and the inside surface of the hole.
The invention provides an improvement to a system of that type.